1. Field of the Invention
This invention relates to a construction of a body structure used in railroad cars or enclosed-type overhead bridges and more particularly to a construction of a body structure that is formed by using frameworks made by press working.
2. Description of the Prior Art
Enclosed body structures include railroad cars shown in FIGS. 6a-6b and 7a-7c as well as overhead bridges and boarding bridges. This specification takes a side structure that makes up the railroad car as an example in the following description.
As shown in these drawings, conventional body structures comprise: a rocker base 1 laid horizontally, which is used as a reference; various kinds of posts such as side door posts 2, slide door end posts 3 and wainscot panel side posts 4, all erected vertically on the rocker
base 1; members such as a belt rail 5, a door pocket belt rail 6, a window header 7 and a door lintel 8, all mounted horizontally to these posts; and a slide door pocket post 9 and a frieze board side post 10, erected vertically with the horizontal members taken as references. These constitutional members are all welded together to form a framework of the body structure. Most of the planes of the framework of the body structure thus formed are lined with a wainscot panel 13, a door pocket plate 14 and a frieze board 15, all welded with reinforcement members 11, 12, to form a body structure having a window 16 and a side entrance 17.
Other conventional examples include a railway car body structure disclosed in Japanese Patent Preliminary Publication No. Showa 61-220962. This structure is comprised of a flat side outside plate and a corrugated compensation plate bound together. The compensation plate is formed with lateral projecting beads, which are triangular in cross section, and with vertical projected strips, which are U-shaped in cross section. Or rectangular corrugations are formed in the compensation plate, and core members are filled between the compensation plate and the side outside plate.
Another conventional example is the Japanese Patent Preliminary Publication No. Showa 61-220963. In this structure, a bead is formed in the direction of shearing force in a drift portion enclosed by the side post and the crosspiece.
These conventional body structures, however, have many drawbacks. The side structure is made of many kinds of and therefore a large number of members, which in turn increases the number of processes in working the members. In addition, the machining itself is complex. At the assembly phase, positioning of components is complex and requires many jigs. Since there are many welding portions, there are greater chances of strain, degrading the dimensional precision.
Furthermore, since the body structures of the Japanese Patent Preliminary Publication No. Showa 61-220962 and 61-220963 employ beads in forming corrugations, the corrugations formed are relatively small and thus their reinforcement effects are necessarily small.